Base station apparatus and communication terminal apparatus

ABSTRACT

A reception quality reporting system may include a communication terminal that measures reception directivity quality in a quality decision signal received from a base station apparatus. The communication terminal decides a switching timing at which directivities of packet data are switched based on directivity switching timing information communicated by the base station and nullifies the reception quality measured in a period before the switching timing. The communication terminal transmits to the base station apparatus reception quality information indicating the measured reception quality.

TECHNICAL FIELD

The present invention relates to a base station apparatus andcommunication terminal apparatus, and more particularly, to a basestation apparatus and communication terminal apparatus thattransmit/receive packet data modulated and coded according to channelquality.

BACKGROUND ART

Conventionally, there is a scheme for a base station to use an adaptivearray antenna and improve transmission quality through transmission withdirectivity.

On the other hand, there is also a scheme called “adaptive modulation”in mobile communications under which a modulation/demodulation scheme isadaptively switched according to fluctuations in reception qualitycaused by fading. Setting an optimum modulation scheme according to acommunication environment allows a large volume of packet data to betransmitted at high speed.

When introducing a technology of an adaptive array antenna to a systemcarrying out adaptive modulation, a communication terminal apparatusmeasures a reception SIR (ratio of a desired signal to interferencesignal) using a common pilot signal (CPICH) transmitted with directivityfrom a base station apparatus as a reference signal. Then, thecommunication terminal apparatus notifies the base station apparatus ofa measured reception SIR. The base station apparatus switches aspreading factor, multi-code multiplexing number, data modulationmulti-valued number and error correcting coding rate according to thenotified reception SIR and sends packet data to the communicationterminal apparatus.

In this case, the base station apparatus performs transmission/receptionwith a plurality of moving communication terminal apparatuses, and it isoften the case that there is a plurality of communication terminalapparatuses requesting reception of high-speed and large-volume packetdata over a wide range of area. In order to transmit packet data withdirectivity to all communication terminal apparatuses requestingreception of high-speed and large-volume packet data, the base stationapparatus needs to transmit the packet data by switching betweendirectivities. Therefore, a reference signal used to measure receptionquality which is the basis for adaptively modulating packet data needsto be transmitted with directivity to obtain accurate reception qualityinformation. Thus, when the adaptive array antenna technology isintroduced to a system carrying out adaptive modulation, the directivitywhen a reference signal is transmitted and the directivity when packetdata is transmitted are switched as appropriate.

However, in the case of a conventional base station apparatus andcommunication terminal apparatus, it may be necessary to often changedirectivity control when communication terminal apparatuses exist over awide range of area and there may exist a time difference in transmissiontiming between a reference signal and packet data, with the result thatalthough adaptive modulation, etc., is performed based on receptionquality measured using the reference signal, the measured receptionquality may not be reflected when packet data is actually transmittedwith directivity. In this case, even if the modulation multi-valuednumber and coding rate, etc., are optimized and packet data istransmitted, there may be a situation in which the communicationterminal apparatus cannot help but receive the packet data with qualitymuch inferior to the expected quality, being unable to demodulate thepacket data or there may also be a situation in which the qualitybecomes by far better than the expected quality, causing the efficiencyof the radio frequency band to decrease, and even if the adaptive arrayantenna technology is introduced to the system carrying out adaptivemodulation, it is not possible to make the most of advantages of bothadaptive modulation and adaptive array antenna technology or maximizecommunication path utilization efficiency.

DISCLOSURE OF INVENTION

It is an object of the present invention to provide a base stationapparatus and communication terminal apparatus capable of receivingpacket data with high quality, providing high efficiency for a radiofrequency band and maximizing communication path utilization efficiency.

This object is attained by the base station apparatus transmitting areference signal with directivity to a terminal using a common pilotchannel, receiving an SIR measured based on the reference signaltransmitted from the terminal and controlling based on the received SIRso that directivity is not changed until adaptively modulated and codedpacket data is transmitted to the terminal with the same directivity asthe directivity with which the reference signal has been transmitted.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a block diagram showing the configuration of a base stationapparatus according to Embodiment 1 of the present invention;

FIG. 2 is a block diagram showing the configuration of a communicationterminal apparatus according to Embodiment 1 of the present invention;

FIG. 3 is a block diagram showing the configuration of a directivityswitching instruction section according to Embodiment 1 of the presentinvention;

FIG. 4 is a flow chart showing the operation of the base stationapparatus according to Embodiment 1 of the present invention;

FIG. 5 is a schematic diagram showing a state of transmission withdirectivity;

FIG. 6 is a block diagram showing the configuration of a base stationapparatus according to Embodiment 2 of the present invention;

FIG. 7 is a block diagram showing the configuration of a communicationterminal apparatus according to Embodiment 2 of the present invention;

FIG. 8 is a block diagram showing the configuration of a directivityswitching instruction section according to Embodiment 2 of the presentinvention;

FIG. 9 is a flow chart showing the operation of the communicationterminal apparatus according to Embodiment 2 of the present invention;

FIG. 10 illustrates a signal according to Embodiment 2 of the presentinvention;

FIG. 11 is a block diagram showing the configuration of a base stationapparatus according to Embodiment 3 of the present invention;

FIG. 12 is a block diagram showing the configuration of a communicationterminal apparatus according to Embodiment 3 of the present invention;

FIG. 13 is a block diagram showing the configuration of a directivityswitching instruction section according to Embodiment 3 of the presentinvention;

FIG. 14 is a block diagram showing the configuration of a directivitynumber information decision section according to Embodiment 3 of thepresent invention; and

FIG. 15 is a flow chart showing the operation of the communicationterminal apparatus according to Embodiment 3 of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference now to the attached drawings, embodiments of the presentinvention will be explained in detail below.

EMBODIMENT 1

FIG. 1 illustrates the configuration of a base station apparatusaccording to Embodiment 1 of the present invention, FIG. 2 illustratesthe configuration of a communication terminal apparatus according toEmbodiment 1 of the present invention and FIG. 3 illustrates theconfiguration of a directivity switching instruction section accordingto Embodiment 1 of the present invention.

The base station apparatus 100 is mainly constructed of antenna elements101-1 to 101-n, reception RF sections 102-1 to 102-n, a directivitycontrol section 103, a received signal demodulation section 104, ascheduler section 105, a transmission signal generation section 106, adirectivity switching instruction section 107 and transmission RFsections 108-1 to 108-n.

Furthermore, the terminal apparatus 200 is mainly constructed of anantenna element 201, a reception RF section 202, a received signaldemodulation section 203, an SIR measuring section 204, a transmissionsignal generation section 205 and a transmission RF section 206.

There is a plurality of antenna elements 101-1 to 101-n, which receivesa signal such as an SIR transmitted from the terminal and outputs thereceived signal to the reception RF sections 102-1 to 102-n.Furthermore, the antenna elements 101-1 to 101-n send reference signalswhich are quality decision signals output from the transmission RFsections 108-1 to 108-n through a common pilot channel and send packetdata output from the transmission RF sections 108-1 to 108-n through adata channel. When there are more antenna elements 101-1 to 101-n, it ispossible to extend the range within which transmission with directivityis possible farther from the base station apparatus.

There are as many reception RF sections 102-1 to 102-n as the antennaelements 101-1 to 101-n and signals input from the respective antennaelements 101-1 to 101-n are subjected to reception processing such asdown-conversion and then output to the directivity control section 103.

The directivity control section 103 which is a directional transmissionsection performs weight control over the received signals input from theplurality of the reception RF sections 102-1 to 102-n using channelestimation and optimum weights, performs processing such as generationof adaptive directivity reception signals and outputs the adaptivedirectivity reception signals generated, etc., to the received signaldemodulation section 104. Furthermore, the directivity control section103 outputs a transmission signal input from the transmission signalgeneration section 106 to the transmission RF sections 108-1 to 108-n asa plurality of weight-controlled transmission signals. Furthermore, thedirectivity control section 103 outputs a transmission terminationsignal to the directivity switching instruction section 107 aftertransmitting packet data and before transmitting the next referencesignal.

The received signal demodulation section 104 carries out demodulationprocessing on the adaptive directivity reception signal, etc., inputfrom the directivity control section 103. Furthermore, the receivedsignal demodulation section 104 supplies an SIR measurement resultreported from each terminal out of the demodulated signal to thescheduler section 105.

The scheduler section 105 decides which terminal is assigned to thechannel for which adaptive modulation is used from the SIR measurementresult which is the quality information input from the received signaldemodulation section 104 and decides the modulation multi-valued numberand coding rate of the signal to the corresponding terminal. Thescheduler section 105 then outputs information on the modulationmulti-valued number and coding rate to the transmission signalgeneration section 106.

The transmission signal generation section 106 which is a packet datageneration section modulates and codes a transmission signal such as areference signal or packet data based on the information on themodulation multi-valued number and coding rate input from the schedulersection 105 and outputs the transmission signal to the directivitycontrol section 103 according to the scheduling by the scheduler section105.

The directivity switching instruction section 107 which is a controlsection monitors whether a predetermined time has elapsed or not andoutputs, when a predetermined time has elapsed and a transmissiontermination signal is input from the directivity control section 103, aninstruction signal for switching between directivities to thedirectivity control section 103. The directivity switching instructionsection 107 will be explained more specifically later.

The transmission RF sections 108-1 to 108-n apply up-conversionprocessing, etc., on the respective weight-controlled transmissionsignals input from the directivity control section 103 and thentransmits transmission signals through the corresponding antennaelements 101-1 to 101-n

Next, the configuration of the terminal apparatus 200 will be explainedusing FIG. 2.

The reception RF section 202 applies reception processing such asdown-conversion processing on the received signal input from the antennaelement 201 and then outputs the received signal to the received signaldemodulation section 203.

The received signal demodulation section 203 carries out predetermineddemodulation processing on the received signal input from the receptionRF section 202. Furthermore, the received signal demodulation section203 outputs the reference signal out of the received signal to the SIRmeasuring section 204.

The SIR measuring section 204 which is a reception quality measuringsection measures an SIR based on the reference signal input from thereceived signal demodulation section 203. The SIR measuring section 204outputs an SIR measured value indicating the calculated receptionquality to the transmission signal generation section 205.

The transmission signal generation section 205 generates a transmissionsignal including the SIR measured value input from the SIR measuringsection 204 and outputs the transmission signal to the transmission RFsection 206.

The transmission RF section 206 applies up-conversion processing, etc.,to the transmission signal input from the transmission signal generationsection 205 and then transmits the transmission signal through thecorresponding antenna element 201.

Next, the configuration of the directivity switching instruction section107 will be explained using FIG. 3. The directivity switchinginstruction section 107 is mainly constructed of a timer 301 and adirectivity switching instruction signal generation section 302.

The timer 301 measures a time and outputs at a predetermined time, asignal indicating that the predetermined time has elapsed to thedirectivity switching instruction signal generation section 302.Furthermore, when a reset signal is input from the directivity switchinginstruction signal generation section 302, the timer 301 resets themeasured time.

Only when a transmission termination signal is input from thedirectivity control section 103, the directivity switching instructionsignal generation section 302 decides whether a signal indicating thatthe predetermined time has elapsed has been input from the timer 301 ornot, and when the signal has been input, the directivity switchinginstruction signal generation section 302 outputs an instruction signalfor switching between directivities to the directivity control section103. Furthermore, after outputting the instruction signal to thedirectivity control section 103, the directivity switching instructionsignal generation section 302 outputs a reset signal to the timer 301.

Next, the operation of the base station apparatus 100 will be explainedusing FIG. 4 and FIG. 5. In FIG. 4, a directivity N is any one ofdirectivities S1 to S4. The directivity switching instruction section107 makes preparations for repeating directivity control processing forthe four preset directivities S1 to S4 (step (hereinafter described as“ST”) 401).

Next, the directivity control section 103 performs control so as totransmit a reference signal with the directivity S1 and transmits thereference signal with the directivity S1 which is the first directivitythrough the transmission RF sections 108-1 to 108-n and antenna elements101-1 to 101-n (ST402).

Next, terminal apparatuses 200 a and 200 b measure an SIR based on thereference signal transmitted with the directivity S1. Then, theterminals 200 a and 200 b transmit the measured SIR to the base stationapparatus 100. Next, the base station apparatus 100 that has receivedthe SIR extracts the SIR measurement result from the received signal atthe received signal demodulation section 104 (ST403).

Next, the base station apparatus 100 transmits packet data with thedirectivity S1 through a channel for which adaptive modulation is usedbased on the SIR (ST404).

The timer 301 of the directivity switching instruction section 107decides whether a predetermined time has elapsed or not (ST405). In thecase where the predetermined time has not elapsed, the directivityswitching instruction section 107 repeats the processes in ST402 toST405. On the other hand, in ST405, in the case where the predeterminedtime has elapsed and it is a time at which directivities can beswitched, the directivity is switched to the next directivity S2 and theprocesses in ST402 to ST405 are repeated (ST406). For the directivity S3and directivity S4, the processes in ST402 to ST405 will be repeatedlikewise. The packet data transmitted with the directivity S1 ismodulated or coded based on the SIR measurement result obtained bytransmitting the reference signal with the same directivity S1, but thepresent invention is not limited to the case where the reference signaland packet data are transmitted with completely the same directivity S1and directivities which are different in some degree may also be usedwithin a certain error range if the effect of this embodiment can be atleast obtained.

Thus, according to this embodiment, directivities are switched after alapse of a predetermined time and after packet data is transmitted, andtherefore it is possible to use the same directivity for a referencesignal and packet data, receive packet data with good quality, enhancethe efficiency of a radio frequency band and maximize the communicationpath utilization efficiency.

EMBODIMENT 2

FIG. 6 illustrates the configuration of a base station apparatusaccording to Embodiment 2 of the present invention, FIG. 7 illustratesthe configuration of a communication terminal apparatus according toEmbodiment 2 of the present invention and FIG. 8 illustrates theconfiguration of a directivity switching instruction section accordingto Embodiment 2 of the present invention. This embodiment ischaracterized in that a base station apparatus notifies a terminal of atiming for switching between directivities. This embodiment differs inFIG. 6 from the embodiment in FIG. 1 in the configuration that adirectivity switching signal generation section 601 is provided anddiffers in FIG. 7 from the embodiment in FIG. 2 in the configurationthat a directivity switching decision section 701 is provided. The samecomponents as those in FIG. 1 and FIG. 2 are assigned the same referencenumerals and explanations thereof will be omitted.

A transmission signal generation section 106 modulates a transmissionsignal such as packet data or a reference signal including a directivityswitching signal input from the directivity switching signal generationsection 601 and then outputs the transmission signal to a directivitycontrol section 103.

The directivity switching signal generation section 601 which is anotification section generates a directivity switching signal based ontiming information for inserting a directivity switching signal inputfrom a directivity switching instruction section 602 and outputs thedirectivity switching signal to the transmission signal generationsection 106 which is a transmission section. The directivity switchingsignal which is directivity switching timing information is a signal fornotifying a terminal of a switching timing at which directivities areswitched, that is, the timing of the slot following the slot includingthe directivity switching signal. The terminal which has received thisdirectivity switching signal can know the timing at which thedirectivity with which packet data is transmitted is switched from adirectivity S1 which is a first directivity to a directivity S2 which isa second directivity. The terminal can know only the timing at whichdirectivity is switched and cannot know to which of directivities S1 toS4 the directivity is changed. Furthermore, it goes without saying thatit is possible to select any directivities from among directivities S1to S4 as directivities before and after switching.

The directivity switching instruction section 602 determines a timingfor switching between directivities from the switching information inputfrom the directivity control section 103 and outputs timing informationfor switching the determined directivity to the directivity controlsection 103. Furthermore, the directivity switching instruction section602 determines to insert a directivity switching signal into the slotimmediately preceding the slot where the directivity with which packetdata is transmitted is changed and outputs information on the timing atwhich the determined directivity switching signal is inserted to thedirectivity switching signal generation section 601. The directivityswitching instruction section 602 will be explained more specificallylater.

When a received signal input from a received signal demodulation section203 includes a directivity switching signal, the directivity switchingdecision section 701 which is a transmission control section instructsan SIR measuring section 204 to nullify an SIR measurement resultmeasured based on a reference signal of the slot including thedirectivity switching signal. On the other hand, when the receivedsignal does not include the directivity switching signal, thedirectivity switching decision section 701 outputs nothing to the SIRmeasuring section 204.

When instructed by the directivity switching decision section 701 tonullify the SIR, the SIR measuring section 204 does not output the SIRmeasurement result to the transmission signal generation section 205. Onthe other hand, when not instructed by the directivity switchingdecision section 701 to nullify the SIR, the SIR measuring section 204outputs the SIR measurement result to the transmission signal generationsection 205.

Next, the configuration of the directivity switching instruction section602 will be explained using FIG. 8. The directivity switchinginstruction section 602 is mainly constructed of a directivity switchingtiming determining section 801 and a directivity switching signalinsertion timing determining section 802.

The directivity switching timing determining section 801 determines atiming for switching between directivities from the switchinginformation input from the directivity control section 103 and outputsthe determined timing information for switching between directivities tothe directivity switching signal insertion timing determining section802.

The directivity switching signal insertion timing determining section802 determines to insert a directivity switching signal into the slotimmediately preceding the slot where directivity is switched based onthe timing information for switching between directivities input fromthe directivity switching timing determining section 801 and outputstiming information on the insertion of the determined directivityswitching signal to the directivity switching signal generation section601. The timing for switching between directivities is not limited tothe case of switching between directivities in the slot following theslot including the directivity switching signal, but it can also be sucha timing at which directivities are switched a predetermined number ofslots after the slot including the directivity switching signal.

Next, the operation of the terminal 700 will be explained using FIG. 9.For example, the terminal 700 that has received a received signalincluding a reference signal transmitted with a directivity S1demodulates the received signal at the demodulation section 203 (ST901).

Next, the directivity switching decision section 701 decides whether thereceived signal includes a directivity switching signal indicating thatthe directivity is switched from the directivity S1 to directivity S2(ST902). When the received signal does not include the directivityswitching signal, the directivity switching decision section 701instructs the SIR measuring section 204 to output the SIR measurementresult (ST903). On the other hand, in ST902 when the received signalincludes the directivity switching signal, the directivity switchingdecision section 701 instructs the SIR measuring section 204 not tooutput the SIR measurement result measured using the reference signaltransmitted with the directivity S1 (ST904).

Next, when the directivity switching signal is included, thetransmission signal generation section 205 generates and transmits atransmission signal not including the SIR measurement result and whenthe directivity switching signal is not included, the transmissionsignal generation section 205 generates and transmits a transmissionsignal including the SIR measurement result (ST905).

FIG. 10 shows a transmission signal which includes a reference signaltransmitted from the base station apparatus through a common pilotchannel on a slot-by-slot basis. A directivity switching signal includesinformation indicating that directivities are switched in the slotfollowing the slot including the directivity switching signal andinstruction information for nullifying an SIR measured based on thereference signal included in slot #1.

Thus, according to this embodiment, by nullifying the SIR measurementresult immediately before directivity switching, it is possible toprevent packet data from being adaptively modulated and coded using awrong SIR measurement result due to directivity switching, receivepacket data with good quality, improve the efficiency of a radiofrequency band and maximize the communication path utilizationefficiency. Furthermore, the terminal can know the timing at whichdirectivities are switched beforehand, and therefore it is possible toprevent SIR measurement results which cannot be used from beingtransmitted and reduce power consumption. Furthermore, since thereference signal and transmission packet data have differentdirectivities, the terminal nullifies an SIR measured based on areference signal interfered by transmission packet data having largetransmit power, and therefore it is possible to prevent the base stationapparatus from adaptively modulating or coding packet data based on aninaccurate SIR measurement result.

EMBODIMENT 3

FIG. 11 illustrates the configuration of a base station apparatusaccording to Embodiment 3 of the present invention, FIG. 12 illustratesthe configuration of a terminal apparatus which is a communicationterminal apparatus according to Embodiment 3 of the present invention,FIG. 13 illustrates the configuration of a directivity switchinginstruction section 1103 according to Embodiment 3 of the presentinvention and FIG. 14 illustrates the configuration of a directivitynumber information decision section according to Embodiment 3 of thepresent invention. This embodiment is characterized in that a basestation apparatus notifies a terminal of directivity switching timingsand directivity number information. This embodiment differs in FIG. 11from the embodiment in FIG. 1 in that a directivity switching signalgeneration section 1101 and a directivity number information generationsection 1102 are provided and differs in FIG. 12 from the embodiment inFIG. 2 in that a directivity switching decision section 1201 and adirectivity number information decision section 1202 are provided. Thesame components as those in FIG. 1 and FIG. 2 are assigned the samereference numerals and explanations thereof will be omitted.

A transmission signal generation section 106 modulates packet data or adirectivity switching signal input from the directivity switching signalgeneration section 1101 and a reference signal, etc., includingdirectivity number information input from the directivity numberinformation generation section 1102 and then outputs the packet data andreference signal to a directivity control section 103.

When timing information on the timing for switching betweendirectivities is input from a directivity switching instruction section1103, the directivity switching signal generation section 1101 generatesa directivity switching signal for notifying a terminal of thedirectivity switching timing and outputs the directivity switchingsignal to the transmission signal generation section 106. Thedirectivity switching signal is a signal for notifying the terminal thatdirectivities are switched in the slot following the slot including thedirectivity switching signal.

The directivity number information generation section 1102 generates adirectivity number information signal based on information ondirectivities S1 to S4 which is the directivity number informationinstructed from the directivity switching instruction section 1103 andoutputs the directivity number information signal to the transmissionsignal generation section 106. Directivities to be switched can beswitched in arbitrary order including the case where directivities S1 toS4 are switched in that order. All directivities may be switched thesame number of times, but the present invention is not limited to thecase where all directivities are switched the same number of times andthe present invention can be adapted so that only some directivities maybe switched more times than others.

The directivity switching instruction section 1103 determines the timingfor switching between directivities from the directivity switchinginformation input from the directivity control section 103 and outputsthe determined directivity switching timing information to thedirectivity control section 103. Furthermore, the directivity switchinginstruction section 1103 determines to insert a directivity switchingsignal in the slot immediately preceding the slot where directivity withwhich packet data is transmitted is switched and outputs the timinginformation on the insertion of the determined directivity switchingsignal to the directivity switching signal generation section 1101.Furthermore, the directivity switching instruction section 1103 notifiesthe switched directivities S1 to S4 to the directivity numberinformation generation section 1102 and instructs the directivity numberinformation generation section 1102 to insert the switched directivityinformation which is information for notifying the directivities S1 toS4 (switched directivities) with which the next packet data to beswitched is transmitted into the transmission signal at the same timingas the timing for inserting the directivity switching signal into thetransmission signal. The timing for inserting directivity numberinformation into the transmission signal is not limited to the casewhere the same timing as the timing for inserting the directivityswitching signal is set, but the directivity number information may alsobe inserted into the transmission signal at a timing different from thetiming for inserting the directivity switching signal. The directivityswitching instruction section 1103 will be explained more specificallylater.

When the received signal input from a received signal demodulationsection 203 includes a directivity switching signal for switching thedirectivity to the slot following the slot including the directivityswitching signal, the directivity switching decision section 1201outputs an instruction for switching to the directivity numberinformation decision section 1202. Furthermore, when outputting thedirectivity switching signal to the directivity number informationdecision section 1202, the directivity switching decision section 1201outputs information on which of directivities S1 to S4 is the nextdirectivity to be switched to the directivity number informationdecision section 1202.

The directivity number information decision section 1202 references thedirectivity number information only when an instruction for switchingbetween directivities is received from the directivity switchingdecision section 1201. Then, the directivity number information decisionsection 1202 compares the current directivity number with thedirectivity number after the directivity switching instructed by thedirectivity switching decision section 1201 in an internal memory (notshown) generates reception quality measuring information for adjustingthe measurement result by an amount in the corresponding qualityvariation between the directivity numbers and outputs the receptionquality measuring information generated to an SIR measuring section 204.

When the reception quality measuring information is input from thedirectivity number information decision section 1202, the SIR measuringsection 204 adjusts the SIR measurement result based on the receptionquality measuring information and outputs the adjusted SIR measurementresult to a transmission signal generation section 205. The SIRmeasurement result output this time becomes SIR measurement results ofthe next directivities S1 to S4 to be switched.

Next, the configuration of the directivity switching instruction section1103 will be explained using FIG. 13. The directivity switchinginstruction section 1103 is mainly constructed of a directivityswitching timing determining section 1301, a directivity switchingsignal insertion timing determining section 1302 and a directivitynumber information insertion timing determining section 1303.

The directivity switching timing determining section 1301 determines atiming for switching between directivities from the switchinginformation input from the directivity control section 103 and outputsthe timing information for switching the determined directivity to thedirectivity switching signal insertion timing determining section 1302.The directivity switching timing determining section 1301 alsodetermines the next directivity to be switched and outputs thedetermined directivity number information to the directivity numberinformation insertion timing determining section 1303.

The directivity switching signal insertion timing determining section1302 determines to insert a directivity switching signal into the slotimmediately preceding the slot where directivities are switched andoutputs timing information for inserting the determined directivityswitching signal to the directivity switching signal generation section1101. The timing for switching between directivities is not limited tothe case where the directivities are switched in the slot following theslot including the directivity switching signal, but the timing forswitching between directivities may also be a timing at whichdirectivities are switched a predetermined number of slots after theslot including the directivity switching signal.

When the directivity number information is input from the directivityswitching timing determining section 1301, the directivity numberinformation insertion timing determining section 1303 determines atiming for inserting the directivity number information into the slotimmediately preceding the slot where directivities are switched andoutputs the timing information for inserting the determined directivitynumber information to the directivity number information generationsection 1102.

Next, the configuration of the directivity number information decisionsection 1202 will be explained using FIG. 14. The directivity numberinformation decision section 1202 is mainly constructed of a directivitynumber information extraction section 1401, a quality variationcalculation section 1402 and a storage section 1403.

The directivity number information extraction section 1401 extractsdirectivity number information from a received signal input from thereceived signal demodulation section 203 and outputs the directivitynumber information to the quality variation calculation section 1402 andstorage section 1403.

When the directivity number information after directivity switching isinput from the directivity number information extraction section 1401,the quality variation calculation section 1402 compares the directivitynumber information with the directivity number information which is thecurrent directivity input from the storage section 1403, calculates aquality variation corresponding to the variation in directivity andoutputs the quality variation to the SIR measuring section 204. When thedirectivity is switched from the directivity S1 to directivity S2, fromthe directivity S2 to directivity S3 and from the directivity S3 todirectivity S4, the quality variation calculation section 1402 is presetto change an SIR measured value by several dB at a time and calculates avariation depending on the range in which directivities are actuallyswitched.

When the directivity number information is input from the directivitynumber information extraction section 1401, the storage section 1403stores the directivity number information input as reception qualitymeasuring information. Furthermore, when the directivity numberinformation which is switched directivity information is input from thedirectivity number information extraction section 1401, the storagesection 1403 outputs the latest directivity number information stored sofar to the quality variation calculation section 1402.

Next, the operation of the terminal apparatus 1200 will be explainedusing FIG. 15. The terminal apparatus 1200 which has received a receivedsignal including a reference signal demodulates the received signal atthe demodulation section 203 (ST1501).

Next, the directivity switching decision section 1201 decides whetherthe received signal includes a directivity switching signal or not(ST1502). When the received signal does not include the directivityswitching signal, the SIR measuring section 204 measures an SIR from thereference signal (ST1503). On the other hand, in ST1502 when thereceived signal includes the directivity switching signal, the SIRmeasuring section 204 measures an SIR corresponding to the qualityvariation calculated by the directivity number information decisionsection 1202 (ST1504).

Next, the SIR measuring section 204 outputs the SIR (ST1505) and thetransmission signal generation section 205 generates and transmits atransmission signal (ST1506).

Thus, according to this embodiment, in addition to the effects of abovedescribed Embodiment 2, it is possible to measure an SIR correspondingto the directivity number information stored beforehand based on thedirectivity number information included in the received signal, andtherefore the terminal apparatus can transmit, before the directivitiesare switched, the SIR measurement result after directivity switching tothe base station apparatus. Furthermore, the base station apparatus canadaptively modulate and code packet data using the SIR measurementresult after directivity switching almost simultaneously with thedirectivity switching, and can thereby select a modulation scheme andcoding rate best suited to the channel quality every time andinstantaneously even when directivities are frequently switched and makethe most of advantages of both the adaptive modulation and adaptivearray antenna technology. Furthermore, the terminal apparatus cancalculate an SIR based on the directivity number information included ina received signal, and thereby obtain a precise SIR speedily and shortenthe processing time.

Embodiments 1 to 3 described above assume that timing for switchingbetween directivities is decided based on a time, but the presentinvention is not limited to the case where timing for switching betweendirectivities is decided based on a time and it is also possible todecide timing for switching between directivities based on thepresence/absence of a terminal which transmits data with urgent priorityor positional information on terminal apparatuses indicating in whicharea more terminals exist, etc. Furthermore, the base station apparatusand terminal according to Embodiments 1 to 3 described above areapplicable to both an HSDPA system and a wireless LAN, etc., other thanthe HSDPA system or also applicable to any system.

As explained above, the present invention can receive packet data withhigh quality, provide high efficiency for a radio frequency band andmaximize the communication path utilization efficiency.

This application is based on the Japanese Patent Application No.2002-327221 filed on Nov. 11, 2002, entire content of which is expresslyincorporated by reference herein.

INDUSTRIAL APPLICABILITY

The present invention is preferably applicable to a base stationapparatus and communication terminal apparatus in particular whichtransmit/receive packet data modulated and coded according to channelquality.

[FIG. 1]

-   100 BASE STATION APPARATUS-   RECEIVED SIGNAL-   TRANSMISSION SIGNAL-   104 RECEIVED SIGNAL DEMODULATION SECTION-   105 SCHEDULER SECTION-   106 TRANSMISSION SIGNAL GENERATION SECTION-   107 DIRECTIVITY SWITCHING INSTRUCTION SECTION-   103 DIRECTIVITY CONTROL SECTION-   102-1 RECEPTION RF SECTION-   102-n RECEPTION RF SECTION-   108-1 TRANSMISSION RF SECTION-   108-n TRANSMISSION RF SECTION    [FIG. 2]-   200 TERMINAL APPARATUS-   RECEIVED SIGNAL-   TRANSMISSION SIGNAL-   203 RECEIVED SIGNAL DEMODULATION SECTION-   204 SIR MEASURING, SECTION-   205 TRANSMISSION SIGNAL GENERATION SECTION-   202 RECEPTION RF SECTION-   206 TRANSMISSION RF SECTION    [FIG. 3]-   FROM DIRECTIVITY CONTROL SECTION 103-   301 TIMER-   302 DIRECTIVITY SWITCHING INSTRUCTION SIGNAL-   GENERATION SECTION-   TO DIRECTIVITY CONTROL SECTION 103    [FIG. 4]-   START-   ST401 PREPARE FOR REPETITION AS MANY TIMES AS DIRECTIVITIES-   ST1402 TRANSMIT REFERENCE SIGNAL WITH DIRECTIVITY N-   ST1403 RECEIVE SIR MEASUREMENT RESULT-   ST1404 TRANSMIT CHANNEL USING ADAPTIVE MODULATION WITH DIRECTIVITY N-   ST1405 ELAPSED PREDETERMINED TIME?-   ST1406 REPEATE AS MANY TIMES AS DIRECTIVITIES-   END    [FIG. 6]-   RECEIVED SIGNAL-   600 BASE STATION APPARATUS-   601 DIRECTIVITY SWITCHING SIGNAL GENERATION SECTION TRANSMISSION    SIGNAL-   104 RECEIVED SIGNAL DEMODULATION SECTION-   105 SCHEDULER SECTION-   106 TRANSMISSION SIGNAL GENERATION SECTION-   602 DIRECTIVITY SWITCHING INSTRUCTION SECTION-   103 DIRECTIVITY CONTROL SECTION-   102-1 RECEPTION RF SECTION-   102-n RECEPTION RF SECTION-   108-1 TRANSMISSION RF SECTION-   108-n TRANSMISSION RF SECTION    [FIG. 7]-   RECEIVED SIGNAL-   700 TERMINAL APPARATUS-   701 DIRECTIVITY SWITCHING DECISION SECTION-   203 RECEIVED SIGNAL DEMODULATION SECTION-   204 SIR MEASURING SECTION-   205 TRANSMISSION SIGNAL GENERATION SECTION-   TRANSMISSION SIGNAL-   202 RECEPTION RF SECTION-   206 TRANSMISSION RF SECTION    [FIG. 8]-   TO DIRECTIVITY CONTROL SECTION 103-   801 DIRECTIVITY SWITCHING TIMING DETERMINING SECTION-   802 DIRECTIVITY SWITCHING SIGNAL INSERTION TIMING DETERMINING    SECTION-   FROM DIRECTIVITY CONTROL SECTION 103-   TO DIRECTIVITY SWITCHING SIGNAL GENERATION SECTION 601    [FIG. 9]-   START-   ST901 DEMODULATE RECEIVED SIGNAL-   ST902 DIRECTIVITY SWITCHING SIGNAL INCLUDED?-   ST903 SIR OUTPUT-   ST904 SIR DISABLED-   ST905 TRANSMIT TRANSMISSION SIGNAL-   END    [FIG. 10]-   DIRECTIVITY SWITCHING SIGNAL-   SLOT #1-   DIRECTIVITY SWITCHING SLOT-   1 SLOT-   1 SLOT    [FIG. 11]-   RECEIVED SIGNAL-   1100 BASE STATION APPARATUS-   1102 DIRECTIVITY NUMBER INFORMATION GENERATION SECTION-   1101 DIRECTIVITY SWITCHING SIGNAL GENERATION SECTION-   104 RECEIVED SIGNAL DEMODULATION SECTION-   105 SCHEDULER SECTION-   106 TRANSMISSION SIGNAL GENERATION SECTION-   1103 DIRECTIVITY SWITCHING INSTRUCTION SECTION TRANSMISSION SIGNAL-   DIRECTIVITY INFORMATION-   103 DIRECTIVITY CONTROL SECTION-   102-1 RECEPTION RF SECTION-   102-n RECEPTION RF SECTION-   108-1 TRANSMISSION RF SECTION-   108-n TRANSMISSION RF SECTION    [FIG. 12]-   RECEIVED SIGNAL-   1200 TERMINAL APPARATUS-   1201 DIRECTIVITY SWITCHING DECISION SECTION-   1202 DIRECTIVITY NUMBER INFORMATION DECISION SECTION-   203 RECEIVED SIGNAL DEMODULATION SECTION-   204 SIR MEASURING SECTION-   205 TRANSMISSION SIGNAL GENERATION SECTION TRANSMISSION SIGNAL-   202 RECEPTION RF SECTION-   206 TRANSMISSION RF SECTION    [FIG. 13]-   TO DIRECTIVITY CONTROL SECTION 103-   1301 DIRECTIVITY SWITCHING TIMING DETERMINING SECTION-   1303 DIRECTIVITY NUMBER INFORMATION INSERTION TIMING DETERMINING    SECTION-   1302 DIRECTIVITY SWITCHING SIGNAL INSERTION TIMING DETERMINING    SECTION-   TO DIRECTIVITY NUMBER INFORMATION GENERATION SECTION 1102-   TO DIRECTIVITY SWITCHING SIGNAL GENERATION SECTION 1101-   FROM DIRECTIVITY CONTROL SECTION 103    [FIG. 14]-   FROM DIRECTIVITY SWITCHING DECISION SECTION 1201-   1401 DIRECTIVITY NUMBER INFORMATION EXTRACTION SECTION-   1403 STORAGE SECTION-   1402 QUALITY VARIATION CALCULATION SECTION-   TO SIR MEASURING SECTION 204-   FROM RECEIVED SIGNAL DEMODULATION SECTION 203    [FIG. 15]-   START-   ST1501 DEMODULATE RECEIVED SIGNAL-   ST1502 DIRECTIVITY SWITCHING SIGNAL INCLUDED?-   ST1503 MEASURE SIR FROM REFERENCE SIGNAL-   ST1504 MEASURE SIR FROM DIRECTIVITY NUMBER INFORMATION-   ST1505 SIR OUTPUT-   ST1506 TRANSMIT TRANSMISSION SIGNAL-   END

1. A communication terminal apparatus comprising: a reception qualitymeasuring section that measures reception quality in a directivity of aquality decision signal using the quality decision signal included in areceived signal; a directivity switching decision section that decides aswitching timing at which directivities of packet data are switchedbased on directivity switching timing information reporting adirectivity switching timing included in the received signal andinstructs the reception quality measuring section to nullify thereception quality measured using the quality decision signal received ina period from a time a predetermined time ahead of the switching timingto the switching timing; and a transmission section that transmitsreception quality information indicating the reception quality measuredusing the reception quality decision signal received at a timing otherthan the period from the time the predetermined time ahead of theswitching timing to the switching timing.
 2. The communication terminalapparatus according to claim 1, wherein the directivity switchingdecision section decides a second slot following a first slot includingthe directivity switching timing information as the switching timing andinstructs the reception quality measuring section to nullify thereception quality measured using the quality decision signal received inthe first slot that is the period from the time the predetermined timeahead of the switching timing to the switching timing.
 3. A base stationapparatus communicating with the communication terminal apparatusaccording to claim 1, the base station apparatus comprising: adirectional transmission section that transmits packet data and aquality decision signal with a directivity; a packet data generationsection that adaptively modulates or codes the packet data based on thequality information; a transmission section that transmits thedirectivity switching timing information; and a control section thatcarries out control to switch directivities with which the packet datais transmitted after transmitting the directivity switching timinginformation.
 4. The communication terminal apparatus according to claim1, further comprising a storage section that prestores reception qualitymeasuring information for each directivity, wherein the receptionquality measuring section measures the reception quality using switcheddirectivity information included in the received signal, the switcheddirectivity information being a next directivity to be switched fortransmitting packet data, and the reception quality measuringinformation.
 5. The base station apparatus according to claim 3,wherein: the transmission section transmits switched directivityinformation to a communicating party, the switched directivityinformation being a next directivity to be switched for transmittingpacket data; the packet data generation section adaptively modulates orcodes packet data based on the quality information in the switcheddirectivity; and the control section transmits the packet data with theswitched directivity.
 6. A reception quality reporting method comprisingthe steps of: at a communication terminal apparatus, measuring receptionquality in a directivity of a quality decision signal using the qualitydecision signal included in a received signal received from a basestation apparatus, deciding a switching timing at which directivities ofpacket data are switched based on directivity switching timinginformation reporting a directivity switching timing included in thereceived signal, and nullifying the reception quality measured using thereception quality decision signal received in a period from a time apredetermined time ahead of the switching timing to the switchingtiming; and transmitting, from the communication terminal apparatus tothe base station apparatus, reception quality information indicating thereception quality measured using the quality decision signal received ata timing other than the period from the time the predetermined timeahead of the switching timing to the switching timing.
 7. The receptionquality reporting method according to claim 6, further comprising,deciding a second slot following a first slot including the directivityswitching timing information as the switching timing, and nullifying thereception quality measured using the quality decision signal received inthe first slot that is the period from the time the predetermined timeahead of the switching timing to the switching timing.